Extension Tree Fruit Team

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The On-Going Brown Marmorated Stink Bug Challenge and Late Season Insect Control

Posted: July 22, 2011

During the last few weeks of scouting orchards, we continued to find all possible forms of brown marmorated stink bug: eggs, adults (individuals from both old overwintering and new summer generations) and all various instars of nymphs. The BMSB was observed not only in stone and pome fruit orchards but also was detected on various wild plants in surrounding vegetation. As of now, we still did not see significant BMSB population build-up on agronomic crops such as soybean or corn. Fortunately, so far (July 22), our extensive BMSB monitoring activities, which include surveying of orchards and border areas around orchards did not detect any rapid movement of BMSB populations from surrounding vegetation into orchards. Although the visual monitoring still remains the best monitoring technique, finally the currently available traps and lures utilizing another stink bug (Plautia stali) aggregation pheromone started to systematically capture BMSB nymphs (no BMSB adults in traps as of now).

The movement of summer adults from outside hosts into orchards (or other crops) and associated deposition of new eggs could become a significant source of new BMSB infestation in orchards. While the nymphal feeding can be reduced by effective and well-timed insecticide treatments (Table 1, in attached pdf), the feeding by continuously wandering BMSB adults is very difficult to control. While at this moment the BMSB pressure from within orchard resident BMSB populations is mostly non-existent, the BMSB adults established outside of the orchards will represent continuous challenges for the rest of this season. With fruit (or for that matter almost any other agronomic or horticultural crop) representing a valuable nutritious food option for stink bugs, more and more BMSB adults will start moving into orchards and depositing eggs on fruit trees. With all other “traditional pests” also present in the orchard, it is becoming very important that the choice of insecticides directed against other pests would also affect, if not control, the portion of BMSB population present in orchards at the time of application. With about 3 more months of BMSB activity to go (until mid-October), it is extremely important that growers plan ahead with the choice of products utilized against BMSB, and preserve the most effective options, with the shortest PHI, for applications when the pressure from this pest will increase, especially in the latter part of the season. Table 1 provides the overview of the most effective insecticides against brown marmorated stink bug adults as well as some label-based information related to PHI and seasonal number of applications and/or maximum use limits.

LATE SUMMER PEST CONTROL

The flight of the second generation of codling moth and the third generation of Oriental fruit moth started in south-central Pennsylvania during the last two weeks. Also, tufted apple bud moth and obliquebanded leafroller are about to start their second generation’s flight. It is very important to closely monitor each pest population, especially in orchards with a previous history of CM, OFM, TABM or OBLR problems. Delegate® at the rate of 4.5 oz or above, Altacor® at the rate of 3.0 oz or above and Belt® at the rate of 5.0 oz or above are highly active against CM, OFM, TABM and OBLR. These recommended products are both excellent and highly effective insecticides against targeted pests, but unfortunately they will not control BMSB and other means may be needed to protect fruit against this troublesome pest.

Due to the existing pressure from BMSB, the incorporation of effective products against stink bugs during late season applications may be warranted for many orchards, especially those located in the southern part of Pennsylvania. Although not every orchard will experience the same pressure from BMSB, we anticipate that most blocks located on the borders of orchards would require special protection against migrating BMSB adults and developing nymphs. Products with active ingredient such as methomyl (i.e.,Lannate SP and Lannate LV; IRAC Group 1A) should not only control BMSB but also help control leafrollers such as TABM and OBLR. Neonicotinoid insecticides (IRAC Group 4A) such as Assail™ 30SG or Belay ® will not only help control various instars of BMSB but also should protect against CM and OFM neonates.

If BMSB is not an important pest at your location, then in orchards with high CM, OFM or other leafroller pressure, insecticide options against “traditional pests” are also available: azinphos-methyl 50W at 1.5-2.0 lb/A (14 day Pre-Harvest Interval [PHI] if less than 2 lb/acre applied: 21 day PHI if more than 2 lb/acre) or Imidan 70W at 3.0-4.0 lb/A (14 day PHI). If growers know that certain insecticides do not provide effective CM control (i.e., due to insecticide resistance), they should consider the use of different compounds with CM activity, not previously used in the problem block (i.e., Avaunt™ at 6 oz/acre (14 day PHI), Calypso™ at 5-6 oz/acre (30 day PHI), Intrepid™ at 16 oz/acre (14 day PHI)), Rimon® at 20-30 fl oz/acre (14 day PHI), Cyd-X at 2-4 oz/acre or Carpovirusine at 6.8-13.5 oz/acre. Pyrethroid insecticides should also provide some control of OFM larvae, but did not perform well in our research trials while tested for their control of CM larvae late during the season. In this group of insecticide chemistries (IRAC Group 3), Danitol ® was the most effective against BMSB adults (Table 1, in attached pdf).

If selective insecticides such as Intrepid or Rimon are to be used to control TABM and OBLR larvae, we recommend 1 to 2 complete applications of these compounds. If using Intrepid at the 12-16 fl oz /acre rate, or Rimon at 20-30 oz/acre only one application may be necessary. If using Intrepid at the 8 fl oz/acre two applications are recommended. The complete spray timings should correspond to 20-30% (2355-2435 DD base 45°) and 60-70% (2665-2740 DD) egg hatch. Please also refer to the product label for rates and application timings. If a low rate of Intrepid (8 fl oz/acre) is used for leafroller control, please note that this compound will not provide adequate control of the internal fruit feeders, Oriental fruit moth or codling moth.

DINOTEFURAN SECTION 18 EMERGENCY EXEMPTION REGISTRATION

A
new active ingredient, dinotefuran received a special Section 18 Emergency
Exemption Registration from US Environmental Protection Agency to help control
brown marmorated stink bug on both pome and stone fruit. This new active ingredient, dinotefuran belongs
to IRAC Group 4A (neonicotinoids), and is available for use on stone and pome
fruit under two trade names: Scorpion® 35SL(manufactured by Gowan Company,
Yuma, AZ) and Venom ® (manufactured by Valent USA Corp, Walnut Creek, CA). The
manufacturer’s recommended rates per acre for Scorpion of 8.0 to 12.0 fl. oz
and for Venom 4.0 to 6.75 oz should provide effective control of BMSB in the
orchards. No more than two applications of dinotefuran containing products are
allowed per season. Both products Scorpion and Venom can be used up to 3 days
before harvest (3d PHI) and have 12 hours Restricted Entry Interval (12h REI). According
to the product label, dinotefuran is highly toxic to bees exposed to treatment
for more than 38 hours following treatment. The Section 18 Emergency Exemption
registration for both products will expire on October 15, 2011.

Based on our direct contact laboratory bioassays conducted
this past winter both dinotefuran containing insecticides were very effective
against BMSB adults, comparable to or better to other available materials. As
of today, we do not have information on activity of this active ingredient
against other orchard pests.

DEGREE-DAY TABLE: Accumulated
degree-days base 43 F from Jan 01 for each reported year (courtesy of SkyBit,
Inc.). The accumulated degree-days for the last date of the current year (Jul
28) mentioned in the table are based on the weather forecast.